Original title: Diabatic Seam Space Sampling for Hydrogen Tunneling Systems with Nuclear-Electronic Orbital Theory
Joseph A. Dickinson, Eno Paenurk, Sharon Hammes-Schiffer · September 2026
Hydrogen atoms can tunnel through energy barriers during chemical and biological reactions, acting like quantum waves rather than classical balls. To study this, scientists need to examine the exact molecule shapes where this tunneling can happen. The researchers developed a new technique called vibronic-SHAKE. It samples matching energy shapes by treating the traveling hydrogen nucleus as a quantum wave within a specialized simulation. They tested this method on two specific molecules with hydrogen and deuterium. They discovered that the connection strength between states changes a lot across these shapes, mostly driven by the distance between the donor and acceptor atoms. Also, the path of the reaction and the direction of coupling change are nearly perpendicular to each other.
You're trying to pass a ball through a crowded hallway without bumping anyone. Normally, you'd wait for a clear path, but here, the people shift positions depending on which way you go, so the path itself changes as you move. In this paper, the hydrogen atom is like the ball, and the hallway is the molecular environment. The method finds all possible paths where the ball can pass without losing energy, even as the environment changes with each move.
Hydrogen tunneling affects many reactions in chemistry and biology. Understanding how it works helps scientists predict reaction speeds, which is key for things like designing drugs or studying enzymes.
The abstract doesn't state limitations explicitly, but the method is applied only to two specific molecules, so its generalizability to other hydrogen tunneling systems isn't established. The use of constrained NEO-MSDFT dynamics may involve approximations not discussed here.
Ask anything about this paper. Answers come from its abstract, and say so when the abstract doesn't cover your question.
Diabatic Seam Space Sampling for Hydrogen Tunneling Systems with Nuclear-Electronic Orbital Theory — Joseph A. Dickinson, Eno Paenurk, Sharon Hammes-Schiffer
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.